1. Field of the Invention
The invention relates to an office system for the processing of a data file by means of at least two simultaneously operational terminals, common processor means, a first number of peripheral apparatus, and a data bus which interconnects the processor means, the terminals and peripheral apparatus.
2. Description of the Prior Art
A terminal station customarily comprises a keyboard for the input of alphanumeric data and control signals, a display device for the display of such alphanumeric data, for example, 25 lines of 40 characters each and possibly further elements such as a foreground memory, a (small) processor and an output apparatus such as a daisy wheel printer. The peripheral apparatus may be inter alia one or more background memories such as a magnetic disc memory, or a highspeed. Systems of this kind are customarily used and offer good results for the processing and filing of text matter consisting of alphanumeric characters which are organized in lines and have fixed shapes. The characters may be matrix characters having a standard dimension of 7.times.9 dots. The set of characters may also be extended with so-called graphic characters so that the text can be elucidated with figures to a given extent.
The work in an office environment involves large quantities of documents. Prior to the input of the data into the memory of the office system, the documents can be converted into series of character codes by means of a character recognition machine. Such OCR machines, however, are expensive and susceptible to errors. Moreover, any documents contain material which cannot be alphanumerically classified, such as figures, signatures, and annotations in the margin. Therefore, it is an object of the invention to enable input of the documents into the system in complete form and without conversion into character codes, the mass data transport then required between a document reader, a memory device and a display device being fast, while bypassing the processor means and hence without prolonged occupation of the latter, so that the processor means require only a limited processing capacity and the office system can still be used simultaneously by different terminals. The object in accordance with the invention is achieved in that for the updating of a document file and the mass data transport between a second number of auxiliary apparatus, that is to say at least:
a. a document reader with pixel-wise scanning of a document field according to a scan pattern;
b. a read/write memory for the reversible storage of the total pixel information of said document field in accordance with said scan pattern;
c. a display device for the display of the total pixel information of said document field;
d. a memory device comprising a digital video disc with optical write and read means for the filing of the total pixel information of said document field; there is provided a switching device which comprises:
A. for each of said auxiliary apparatus a switching module which has a first connection for the associated auxiliary apparatus, a second connection to said data bus, a third connection and a control connection, the first and the second connection being transparently interconnected in a first state of the switching module, while the first and the third connection are interconnected in a second state of the switching module;
B. at least one first and one second internal data highway whereto all said third connections are coupled;
C. a control member which includes a first control line which is connected to the data bus in order to receive control and selection signals and to despatch reply signals and which also has associated control outputs which are connected to the control connections of associated switching modules in order to carry a selection signal for activating said first or said second state, as desired, and in order to form in said second state, two coexistent pairs from four of said second number of auxiliary apparatus, said pairs being interconnected via said first and said second internal data highway, respectively, said control member furthermore having a signalling input for receiving a termination signal after termination of a mass data transport and for releasing the relevant data highway in reaction thereto;
D. a data flow control element for realizing a mass data transport of the pixel information of a document field in said second state of the switching module, synchronized in a handshake by synchronization signals which are also carried on the internal data highway. In the switching device an attractive separation is thus realized between on the one hand the mass data transport between the various auxiliary apparatus and on the other hand the adaptation of the switching device to the auxiliary apparatus. Furthermore, each of the auxiliary apparatus is connected via a respective separate switching module to either the data bus and hence to processor/terminals or to the internal data highway. As a result, the construction of the switching modules remains simple, without giving rise to congestion at the level of these switching modules; such congestion is removed, if necessary, at the level of the data bus, for example, by an arbitrating processor or a distributed arbitration mechanism. Furthermore, the processor need not continuously monitor the mass data transport between the auxiliary apparatus, so that a comparatively simple processor suffice. The switching device may also have a modular construction, which implies that it can be readily extended, both as regards the number of switching modules/auxiliary apparatus as well as regards the number of internal data highways within the switching device. "Transparent" is to be understood to mean herein that the organization is such that any buffering within the switching module has a depth of at the most one elementary data group (e.g. bit or byte).
When use is made of a third number of n internal data highways, the third connection in each switching module preferably has n lines, each of which is coupled to a relevant internal data highway, each switching module preferably having n second states for performing a 1-out-of-n selection from said n lines. The internal data highway itself may thus have a very simple construction and the selection function is present within the switching module. The mass data transport can then be monitored and synchronized by the auxiliary apparatus themselves. Thus, an auxiliary station itself can interrupt or terminate the mass data transport, if desired.
Preferably, for the memory device comprising a digital video disc there is provided a storage device having k separate storage positions and a common loading position for the memory device and the storage device, there being provided a selection/transport device for transporting a selectable video disc between the associated storage position and the loading position, said storage device having a second control member which is connected to said data bus as a further peripheral apparatus. The mechanical organization of a memory device comprising a plurality of video discs is described in the previous U.S. patent application Ser. No. 298,843, filed Sept. 3, 1981 and assigned to the assignee of the present application, which is incorporated herein by way of reference. When the control member thereof is constructed as a peripheral apparatus of the data bus/processor means, an attractive separation is made between the electromechanical selection of the amount of data to be transported and the actual mass data transport; during the electromechanical selection only a limited number of instructions must be transported; this can be readily realized via the data bus. It has also been found that an attractive modular construction of the memory device comprising video discs can thus be realized. After all, the electromechanical selection and presentation of a video disc from a storage position is very slow in comparison with the electronic/electromechanical selection of a data block on a video disc; this consideration also favors the construction of the control member as a peripheral apparatus.